Imaging Control Device Apodization Effect via F-Number Variation
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Solution Overview
Problem
Existing imaging systems face challenges in achieving an optimal apodization effect without using an apodization filter, as they often result in uneven blurriness across the captured image due to inconsistent exposure times and difficulty in controlling exposure time with mechanical shutters.
Innovation Solution
An imaging control device and method that synchronizes the exposure start and end times across the entire imaging surface, while sequentially changing the F-number of the stop during exposure based on a function representing the light transmittance relationship with distance from the optical axis center, mimicking the apodization filter's effect without its use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a focal plane shutter is used to control exposure time, then exposure can be controlled during imaging, but the start timing of exposure cannot be uniformed in the entire imaging surface, resulting in uneven blurriness across the captured image
Solution Approach 1:
The patent divides the imaging surface into multiple regions (first imaging region and second imaging region) and applies different F numbers to each region during exposure. This segmentation allows independent control of blur characteristics in different areas, resolving the uniformity issue while maintaining exposure time control.
Solution Approach 2:
The patent applies different optical properties (different F numbers) to different regions of the imaging surface. The first imaging region uses a first F number while the second imaging region uses a second F number, creating local quality variations that achieve uniform blurriness across the entire image despite using a focal plane shutter.
2Reliability
If an apodization filter is used to improve out-of-focus images, then the contours of the blurred image can be smoothed, but the cost of the lens device becomes high and AF performance may be affected
Solution Approach 1:
The patent replicates the apodization effect by using multiple stops with different F numbers in different regions, rather than using a physical apodization filter. This copying of the optical effect through computational control achieves the same blurred image quality improvement without the high cost and structural complexity of an actual apodization filter.
Solution Approach 2:
The patent changes the F number parameter across different regions of the imaging surface during exposure. By varying the F number (from first F number to second F number) in different regions, the system achieves apodization-like effects that smooth blurred image contours without requiring a physical apodization filter.
3Reliability
If the stop is changed during exposure using a focal plane shutter, then the APD effect can be obtained, but the degree of blurriness is changed in the upper and lower parts of the captured image
Solution Approach 1:
The patent segments the imaging surface into distinct regions with different F number settings. By assigning the first F number to the first imaging region and the second F number to the second imaging region, the system prevents the uniformity problem that occurs when a single stop is changed during exposure, while still achieving the desired APD effect in each region.
Solution Approach 2:
The patent implements local quality control by allowing different parts of the imaging surface to have different F numbers simultaneously. This resolves the contradiction by ensuring that while the APD effect is achieved through F number variation, the blurriness remains uniform across the entire image through coordinated regional control.
Data Source
AI summary
A digital camera that includes an imaging sensor having a stop 2 arranged in front of an imaging surface includes an imaging control unit that starts exposure of pixels on the entire imaging surface at the same time and then, ends the exposure of the pixels at the same time in a state where light from a subject is incident on the imaging surface, by controlling an imaging sensor drive circuit which drives the imaging sensor, and a processor that sequentially changes an F number of the stop 2 to a plurality of values during a period from the start of the exposure until the end of the exposure. The processor controls a time in which the F number is maintained at each of the plurality of values to be a time that is based on a function indicating light transmittance characteristics of an APD filter.